Modern Vespa

Here's a pretty graph I just made from the telemetry of a recent long ride in the country for you to ponder

So what is it? It's Speed on (dashboard) vs RPM *while accelerating*. (for stable speed scroll down)

Vertical is 0-140kmph and Horizontal is 2000-9000rpm.

you can see that 100kmph is approx 7000rpm and then when increasing from there the variator has already reached max so the speed and rpm increase together up to 129kmph/9000rpm


Recorded on my Supertech with the belt+rollers being about 8000km old

And if you only ride around the city (and one brief trip on the freeway) you get a graph like this

.... Which has a remarkable resemblance to a murmeration of Starlings.

lol, i didn't notice

Ok, so you may have Starlings in your engine. This could be very serious. Is the engine making "chirping" sounds? If they are in there we need to work out how to remove them! Dont ride it again until you get them out...

Must be all the country riding i do. Maybe if i modified my airbox then they could escape 🤔

I simply recorded rpm vs speed at a stable speed and the rpm during wide-open acceleration. Not Vespa.

I like this one...

Here you can see when from the Hwy they are about to enter the city...

I strongly suggest modding it with some holes!

much cleaner graph for "stable speeds". (hold speed steady for 1sec or more). This is the same data set (long ride in the country) but with a different filter

Well that didn't work

What didn't?

Me trying to post my findings

Can you give some more info on what you used to record this data?

I use the Android App that I created called VespaSnoop which is similar to the official Vespa app. This uses Bluetooth to connect to my Supertech* to record many things such as RPM and Speedo (and temperature etc). https://play.google.com/store/apps/details?id=com.steelbytes.vespasnoop


* should also work with bikes such as a 75" Anniversary GTS or Primavera or an HPE with the optional PMP2 module or some of the other Piaggio scoots and bikes. (Many use the same Bluetooth protocol).

I use a tach and a digital speedo. I suppose I'll have to relearn how to make a chart on Libre Office.

And then glance down at the tach+speedo and remember the numbers? or do you have a record mechanism?

Old skool. I have a pad and a pencil.

But, if you are holding a pencil, how do you accelerate?

Well don't use Libre Office to graph it. Get out a ruler and draw a graph on paper then scan it take a photo 📐✏️

I've heard of people arranging their phones to take video of the tach and speedometer as they ride around, and then manually pulling pairs of readings from the video every few seconds from the comfort of their computers. That would produce these "starling" scatterplots, although with fewer birds in the flock. Another interesting way of using the data is to plot accelerative runs by time, so you can see specific RPM/speed runups and get a better sense of how the CVT adjusts to convert engine speed into ground speed.

I was curious to do this with my Scarabeo but the aftermarket tachometer I installed is highly damped - or perhaps the display simply doesn't refresh very often - so the RPMs lag by a noticeable amount. That damping effect really reduces the value of the information a tach provides.

The graph simply is explained by the variator transmission the scooter has.

Yes, i know. I'm quite aware how my Vespa works including its CVT

I think he took your first post as a question...

updated to show stable (green) and acceleration (red)

Steady speed.

But fortunately, I also have a brain and memory.

That's it... That's the secret...

But can you do 10 samples pretty second over thousands of kms? 😝

No, because I am looking at differences not just posting pictures.



Speed in kms
Blue = stock
Red = dr.pulley variator and 11g TechPulley weights

So lighter weights do not always equal lower speed.
Dr. Pulley Variator on my scoot is 105mm diameter vs 102mm for stock.

Not on the graph. Stall speed and speed during acceleration

stock stall 3150 and modified stall 5500
Stock rpm during max acceleration 5300
Dr.Pulley variator with 11g weights rpm during max acceleration 6600/7200 depending on load. 6600 on the flat, 7200 uphill with passenger.

I would say, they never did...

Agreed but some myths die hard.

In a geared car, your top speed just depends on the final gear ratio, irrespective of what you do with the gears getting there. Same with a variator when it maxes out. Heavier weights just mean you get into "top gear" sooner and so probably lose some acceleration. With much lighter roller weights you might not get to "top gear", and then max speed will not be achieved.

A different variator, roller size, sliders, belt length, etc can effect the final ratio and hence the top speed.